Question

目前我正在进行文件上传，基本上当我选择文件时我可以编辑他的宽度和高度以及其他东西，但我的问题与宽度和重量有关，基本上我需要的是获得宽度和原始图像大小的高度，此刻我可以改变它，它工作得很好。

所以我有这个：

<div id="holder" class="col-md-offset-2">
            <div v-if="!image">
                <input type="file" @change="onFileChange">
            </div>
            <div v-else>
                <div class="col-md-6">
                    <div class="form-group">
                        <label class="control-label col-md-2">width</label>
                        <div class="col-md-10">
                            <input class="form-control" v-model="docImage.width" type="number" />
                        </div>
                    </div>
                    <div class="form-group">
                        <label class="control-label col-md-2">height</label>
                        <div class="col-md-10">
                            <input class="form-control" v-model="docImage.height" type="number" />
                        </div>
                    </div>


data() {
    return {
        image: '',
        docImage: {
            key: 'Image',
            width: '100',
            height: '100',
            base64: "",
            align: "left",
        },
        alignChoices: [
            'left',
            'right',
            'center'
        ]

    }
},

onFileChange(e) {
            var files = e.target.files || e.dataTransfer.files;
            if (!files.length)
                return;
            this.createImage(files[0]);
        },
        createImage(file) {
            var image = new Image();
            var reader = new FileReader();
            var vm = this;

            reader.onload = (e) => {
                vm.image = e.target.result;
                vm.docImage.base64 = vm.image.split(",")[1]; // get the base64 string defined after the comma
            };
            reader.readAsDataURL(file);
        },
        removeImage: function (e) {
            this.image = '';
        },

Answer 1

以下是摘录。

window.URL    = window.URL || window.webkitURL;
var elBrowse  = document.getElementById("browse"),
    elPreview = document.getElementById("preview"),
    useBlob   = false && window.URL; // Set to `true` to use Blob instead of Data-URL

// 2.
function readImage (file) {

  // Create a new FileReader instance
  // https://developer.mozilla.org/en/docs/Web/API/FileReader
  var reader = new FileReader();

  // Once a file is successfully readed:
  reader.addEventListener("load", function () {

    // At this point `reader.result` contains already the Base64 Data-URL
    // and we've could immediately show an image using
    // `elPreview.insertAdjacentHTML("beforeend", "<img src='"+ reader.result +"'>");`
    // But we want to get that image's width and height px values!
    // Since the File Object does not hold the size of an image
    // we need to create a new image and assign it's src, so when
    // the image is loaded we can calculate it's width and height:
    var image  = new Image();
    image.addEventListener("load", function () {

      // Concatenate our HTML image info 
      var imageInfo = file.name    +' '+ // get the value of `name` from the `file` Obj
          image.width  +'×'+ // But get the width from our `image`
          image.height +' '+
          file.type    +' '+
          Math.round(file.size/1024) +'KB';

      // Finally append our created image and the HTML info string to our `#preview` 
      elPreview.appendChild( this );
      elPreview.insertAdjacentHTML("beforeend", imageInfo +'<br>');

      // If we set the variable `useBlob` to true:
      // (Data-URLs can end up being really large
      // `src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADAAAAA...........etc`
      // Blobs are usually faster and the image src will hold a shorter blob name
      // src="blob:http%3A//example.com/2a303acf-c34c-4d0a-85d4-2136eef7d723"
      if (useBlob) {
        // Free some memory for optimal performance
        window.URL.revokeObjectURL(image.src);
      }
    });
		
    image.src = useBlob ? window.URL.createObjectURL(file) : reader.result;

  });

  // https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readAsDataURL
  reader.readAsDataURL(file);  
}

// 1.
// Once the user selects all the files to upload
// that will trigger a `change` event on the `#browse` input
elBrowse.addEventListener("change", function() {

  // Let's store the FileList Array into a variable:
  // https://developer.mozilla.org/en-US/docs/Web/API/FileList
  var files  = this.files;
  // Let's create an empty `errors` String to collect eventual errors into:
  var errors = "";

  if (!files) {
    errors += "File upload not supported by your browser.";
  }

  // Check for `files` (FileList) support and if contains at least one file:
  if (files && files[0]) {

    // Iterate over every File object in the FileList array
    for(var i=0; i<files.length; i++) {

      // Let's refer to the current File as a `file` variable
      // https://developer.mozilla.org/en-US/docs/Web/API/File
      var file = files[i];

      // Test the `file.name` for a valid image extension:
      // (pipe `|` delimit more image extensions)
      // The regex can also be expressed like: /\.(png|jpe?g|gif)$/i
      if ( (/\.(png|jpeg|jpg|gif)$/i).test(file.name) ) {
        // SUCCESS! It's an image!
        // Send our image `file` to our `readImage` function!
        readImage( file ); 
      } else {
        errors += file.name +" Unsupported Image extension\n";  
      }
    }
  }

  // Notify the user for any errors (i.e: try uploading a .txt file)
  if (errors) {
    alert(errors); 
  }

});

#preview img{ height:100px; }

<input id="browse" type="file" multiple>
<div id="preview"></div>

具有vuejs的图像文件的原始大小

1 个答案: